The use of registries as an adjunct or alternative to randomized controlled trials in medical research, coinciding with the rapid growth of social networking, has produced a burgeoning phenomenon - patient-generated health registries. Increasingly these registries are being used in medical research. In some, participants are indicating their willingness to be enrolled in clinical trials or other research studies; in others it is the information in the registries that is the data used by scientists in medical and behavioral research. This project proposed by the American Association for the Advancement of Science (AAAS) will include both types of databases. This project will identify as many of these registries as possible, using multiple search strategies; create a profile of each registry, using information provided on their websites, as well as with interviews with self-identified organizers of the patient communities; characterize the registries on the basis of the data elements they contain, as well as information about the registries' privacy, confidentiality, and data management policies; and describe how scientists have used the registries in their research. The data from the registry profiles will be aggregated and a report prepared describing the project's findings and conclusions. The data generated from this project will be integrated with AHRQ's high-priority Registry of Patient Registries (RoPR) project. Although AHRQ has developed an expertise in patient registries, resulting in the publication of two editions of Registries for Evaluating Patients: A User's Guide, their focus has been on professionally-generated registries, with no information on registries generated by online patient communities. This project will complement the work of AHRQ by opening up a new field of inquiry, examining such areas as how these registries are organized, their value in medical research, and related ethical and public policy issues.